Journal of Science
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Item Applied magnetic field and stress induced anisotropy dependence of energy for oriented ferromagnetic thick films(University of Kelaniya, 2008) Samarasekara, P.The energy of perfectly oriented thick ferromagnetic films at different applied magnetic field and stress was studied using classical model of Heisenberg Hamiltonian. For the values of parameters used in this report, the energy required to orient the film with 1000 layers in 41.4° or 57.6° directions becomes minimum at applied magnetic fields of ω Hout = 4.8 or ω Hin = 4.8, respectively. The film can be easily oriented in 172° direction by applying the external stress ω Ks = 3.6 perpendicular to the film plane, for the values of parameters used in this report. These final results mainly depend on the values of other parameters used for calculations. The energy becomes minimum and maximum at almost the same values of oriented angle (θ), in plane magnetic field, out of plane magnetic field and stress for both sc(001) and bcc(001 lattice types. But the values of energies corresponding to maxima and minima are slightly different for the sc(001) and bcc(001) lattices.Item Investigation of anisotropy constants dependence of ultra-thin ferromagnetic films with second order perturbed Heisenberg Hamiltonian(University of Kelaniya, 2007) Samarasekara, P.The variation of energy of ferromagnetic ultra-thin films with second and fourth order anisotropy was investigated using Heisenberg Hamiltonian with second order perturbation. The study was limited to sc(001) film with three layers. Graphs indicate energy minimums at certain values of second order anisotropy, fourth order anisotropy and angle. Films with fourth order anisotropy ω )4( Dm =4 can be easily oriented in the direction given by angle of 2.66 radians for the values of other energy terms used in this simulation. When the second order anisotropy ( ω )2( Dm ) is 3.1, preferred direction is 0.754 radians. When the second order anisotropy varies at a constant value of fourth order anisotropy, the graph indicates more energy minimums.